Primary vesicoureteral reflux (VUR) is a common problem, occuring [sic] in 8-50% of children with urinary tract infection (UTI). It has the potential for causing irreparable renal damage, particularly [sic] in younger children. Despite the widespread use of antibiotic prophylaxis in children with VUR, there are no placebo-controlled studies demonstrating its clinical benefit in preventing renal injury. The main aim of our proposed double blind, placebo-controled [sic] study is to test the hypothesis that prolonged antibiotic prophylaxis in children >2 years old with grade I-IV VUR is unnecessary. Our study, which is a joint effort of 28 Pediatric Nephrologists and 9 Pediatric Urologists from 28 centers affiliated with the North American Pediatrics Renal Transplant Registry (NAPRTCS) and the Midwest Pediatric Nephrology Consortium (MWPNC) will test this hypothesis by recruiting 120 children up to the age of 10 years with newly diagnosed grades I-IV VUR. We propose using antibiotic prophylaxis in all eligible subjects up to the age of 2 years or a minimum of 6 months from the diagnosis of VUR (whichever comes later) and subsequently randomizing them into prophylaxis and placebo groups. Children >2 years old will be randomized directly at study entry into prophylaxis and placebo groups. Followup will include biannual clinc [sic] visits;yearly renal imaging, blood and urine tests, and assessment for dysfunctional voiding (DV) and constipation;and the measurement of glomerular filtration rate by iohexol clearance. By randomization, we will test our first hypothesis that antibiotic prophylaxis after age 2 years does not decrease the frequency of UTI, reduce the risk of renal scarring, or enhance resolution of VUR. By using objecitve [sic] scoring for DV and constipation, we will test our second hypothesis that their presence delays resolution of VUR, and increases the frequency of UTI and renal scarring, irrespective of long-term antibiotic prophylaxis. Patients who fail medical management will be randomized into Delfux or surgical reimplantation groups to test our third hypothesis that the two treatments do not differ in cure rate, recurrence rate of UTI, or risk of renal scarring. Vesicoureteral reflux, the abnormal flow of urine from the bladder into the kidneys, is common in children and may cause kidney damage and high blood pressure. Current treatment uses daily antibiotics for years, but this may not be necessary and may cause some harm, inlcuding [sic] resistance to antibiotics, requiring children to have expensive and painful radiology tests and surgical procedures, and causing parental anxiety. This study will determine if long-term antibiotics are necessary in children with VUR